One type of extracorporeal blood processing is an apheresis procedure in which blood is removed from a donor or patient, directed to a blood component separation device such as a centrifuge, and separated into red blood cells, white blood cells, platelets, plasma or other blood components for collection or therapeutic purposes. One or more of these blood component types are collected, while the remainder is returned to the donor or patient.
An apheresis system includes a blood component separation device, such as a membrane-based separation device or a centrifuge, which separates blood into red blood cells, white blood cells, platelets, or plasma. In one embodiment, the separation device includes a rotor containing a channel that receives a blood-processing vessel. Typically, an extracorporeal tubing circuit connects a healthy human donor or a patient suffering from some type of illness with the blood-processing vessel. The blood processing vessel and extracorporeal tubing circuit collectively define a sterile system. When the fluid connection is established, blood may be extracted from the donor/patient (hereafter, “donor”) and directed to the blood component separation device such that at least one type of blood component may be separated and removed from the blood, either for collection or for therapy. Peristaltic pumps on the separation device act on segments of the tubing circuit to extract blood from the donor, direct it to the appropriate processing location, add appropriate amounts of anti-coagulant, store separated blood components, and, finally, return residual blood components to the donor. It is advantageous that the relative action of the pumps be known, so that the appropriate amounts of fluid can be used in the blood separation process. Since a new tubing circuit is uniquely installed in the device for each donation, and since there may be variation between tubing circuits and in the exact interconnection between the tubing circuit and the separation device, it would be advantageous if the action of the pumps could be tested in connection with each donation.